Later this month a special commission will convene in Maine to study ocean acidification and look for ways to mitigate it. It was established by legislation passed in April, making Maine the first state on the East Coast to enact a law specifically to study the threat posed by the changing chemistry of the seas. The lawmaker behind the measure says ocean acidification is a problem he witnesses on a daily basis. Tom Porter has the story.

Rep. Mick Devin (right) and volunteer Dave Cheney with some of the shellfish they're studying at the Darling Center.

Mick Devin is a Democratic state representative for District 51, which includes the coastal communities of Bristol, Damariscotta and Newcastle. He's also a marine biologist at the University of Maine's Darling Center.

"So this room is used to conduct studies," he says. Here at the shellfish hatchery, water pumps continuously circulate thousands of gallons of seawater through here every day. Constantly running water is essential, says Devin, which is why there's a backup generator in case of a power failure.

The room contains a number of water tanks, each containing different types of oysters and clams in various stages of their lifecycle - from the larval phase (right) through to fully grown.

In recent years, Devin says he's noticed a worrying development in the pace of this lifecycle. "It seems in the last couple of years I've struggled with getting my oyster larvae to settle," he says, meaning it takes them longer to develop and grow into mature oysters.

A phase which used to take between 17 and 20 days, he says, now takes noticeably longer. "Is that due to ocean acidification? We don't know," he says. "But certainly there is some sort of change which is causing my oyster larvae to take longer to settle."

What is known, says Devin, is that more carbon dioxide is entering the ocean, creating carbonic acid. This is having an impact on marine life, most notably bivalves such as oysters and clams, causing their shells to dissolve.

He says these changes in the PH level of the ocean have been especially noticeable on the West Coast: Shellfish hatcheries in the state of Washington, for example, lost more than 50 percent of their seed two years ago. Here on the East Coast, Devin says Maine is the state most affected by ocean acidification.

"In addition to the CO2, Maine has an incredible fresh water input into our coastal waters," he says. "We have major river systems from New Hampshire all the way up to Calais and Saint John (New Brunswick), so those rivers are another source of chemicals and compounds that are causing ocean acidifcation."

"I've been digging clams since I was 12 years old," says Dave Cheney, a third-generation clam digger from the Newcastle area. Nowadays he farms oysters and helps out at the UMaine hatchery as a volunteer. Since he started clam-digging in 1980, he's witnessed major changes in the environment, and the economic consequences of those changes.

"Back when I first started digging we had one cove, the eastern branch, that had between 15 and 20 diggers in it every single day. Now that cove might have two or three part-time diggers per week," Cheney says. "So I've seen the flats go from highly productive to, 'This is probably the worst I've ever seen it.'"

Ocean acidification has worrying implications for Maine's shellfish farming industry, which has seen steady growth in recent years, as diners across the nation are increasingly drawn to bivalves - especially oysters. Just a couple of miles up the road from the Darling Marine Center is one of the state's most established oyster producers.

Bill Mook (right) operates Mook Sea Farm, a 6,000-square-foot facility on five acres of land, where the Damariscotta river meets the ocean. For nearly 30 years, Mook has been rearing American oysters from egg to adult size. "We're standing right now in the hatchery," he says.

Mook Sea Farm sells between 80 million and 100 million oysters a year - either in seed form for other farmers to cultivate, or as fully-grown ready-for-market oysters. Mook says he began noticing strange things happening about five years ago, including diminishing algae blooms and slower-growing oyster larvae, all of which he attributes to the increasing acidity of the ocean.

Based on this assumption, Mook says he developed a number of strategies to try and minimize the effects of the changing environment. Nevertheless, he is extremely worried by the implications of ocean acidification, which is so poorly understood.

"There are all these other variables that are operating, and I think one of the big challenges that we have - and the commission, I hope, will be dealing with this - is to try to sort out the relative importance of these different things: runoff, increasing temperature - all of those types of things."

"Getting the bill into law was the easy part," says Rep. Mick Devin. He says the real work starts with the commission, and whatever recommendations it brings forth.

"And then it's going to be really tough, because I think those recommendations are going to, (a) have a price tag because there's going to be a cost, and number two, probably going to involve a behavior change, and as we all know it's tough for people to change their behavior."

Mick Devin will among the guests on Thursday's Maine Calling program on ocean acidification, which airs on MPBN Radio from noon to 1 p.m.